dhcp,network: implement RFC 4833 (DHCP Timezone option)

This one is simply to add: encode the tzdata timezone in the DHCP
options and optionally make use of it.

6 files changed, 88 insertions, 3 deletions

diff --git a/src/network/networkctl.c b/src/network/networkctl.c
index c9b53dc3f6..2281d4b718 100644
--- a/src/network/networkctl.c
+++ b/src/network/networkctl.c
@@ -497,7 +497,7 @@ static int link_status_one(
                 sd_hwdb *hwdb,
                 const char *name) {
         _cleanup_strv_free_ char **dns = NULL, **ntp = NULL, **domains = NULL;
-        _cleanup_free_ char *setup_state = NULL, *operational_state = NULL;
+        _cleanup_free_ char *setup_state = NULL, *operational_state = NULL, *timezone = NULL;
         _cleanup_netlink_message_unref_ sd_netlink_message *req = NULL, *reply = NULL;
         _cleanup_device_unref_ sd_device *d = NULL;
         char devid[2 + DECIMAL_STR_MAX(int)];
@@ -570,7 +570,6 @@ static int link_status_one(
         setup_state_to_color(setup_state, &on_color_setup, &off_color_setup);
 
         sd_network_link_get_dns(ifindex, &dns);
-        sd_network_link_get_ntp(ifindex, &ntp);
         sd_network_link_get_domains(ifindex, &domains);
         r = sd_network_link_get_wildcard_domain(ifindex);
         if (r > 0) {
@@ -652,6 +651,8 @@ static int link_status_one(
                 dump_list("             DNS: ", dns);
         if (!strv_isempty(domains))
                 dump_list("          Domain: ", domains);
+
+        (void) sd_network_link_get_ntp(ifindex, &ntp);
         if (!strv_isempty(ntp))
                 dump_list("             NTP: ", ntp);
 
@@ -661,6 +662,10 @@ static int link_status_one(
         if (!strv_isempty(carrier_bound_by))
                 dump_list("Carrier Bound By: ", carrier_bound_by);
 
+        (void) sd_network_link_get_timezone(ifindex, &timezone);
+        if (timezone)
+                printf("       Time Zone: %s", timezone);
+
         return 0;
 }
 
diff --git a/src/network/networkd-dhcp4.c b/src/network/networkd-dhcp4.c
index 1b2ff7c769..7fce389fa2 100644
--- a/src/network/networkd-dhcp4.c
+++ b/src/network/networkd-dhcp4.c
@@ -624,6 +624,11 @@ int dhcp4_configure(Link *link) {
                         return r;
         }
 
+        /* Always acquire the timezone */
+        r = sd_dhcp_client_set_request_option(link->dhcp_client, DHCP_OPTION_NEW_TZDB_TIMEZONE);
+        if (r < 0)
+                return r;
+
         if (link->network->dhcp_sendhost) {
                 _cleanup_free_ char *hostname = NULL;
                 const char *hn = NULL;
diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index cc9dc393c6..c179aafebb 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -672,6 +672,27 @@ static int link_enter_set_addresses(Link *link) {
                         return r;
                 */
 
+                if (link->network->dhcp_server_emit_timezone) {
+                        _cleanup_free_ char *buffer = NULL;
+                        const char *tz;
+
+                        if (link->network->dhcp_server_timezone)
+                                tz = link->network->dhcp_server_timezone;
+                        else {
+                                r = get_timezone(&buffer);
+                                if (r < 0)
+                                        log_warning_errno(r, "Failed to determine timezone: %m");
+                                else
+                                        tz = buffer;
+                        }
+
+                        if (tz) {
+                                r = sd_dhcp_server_set_timezone(link->dhcp_server, tz);
+                                if (r < 0)
+                                        return r;
+                        }
+                }
+
                 r = sd_dhcp_server_start(link->dhcp_server);
                 if (r < 0) {
                         log_link_warning_errno(link, r, "Could not start DHCPv4 server instance: %m");
@@ -2414,6 +2435,14 @@ int link_save(Link *link) {
         }
 
         if (link->dhcp_lease) {
+                const char *tz = NULL;
+
+                r = sd_dhcp_lease_get_timezone(link->dhcp_lease, &tz);
+                if (r >= 0)
+                        fprintf(f, "TIMEZONE=%s\n", tz);
+        }
+
+        if (link->dhcp_lease) {
                 assert(link->network);
 
                 r = sd_dhcp_lease_save(link->dhcp_lease, link->lease_file);
diff --git a/src/network/networkd-network-gperf.gperf b/src/network/networkd-network-gperf.gperf
index 7ac7ef1ea3..c8c612d4eb 100644
--- a/src/network/networkd-network-gperf.gperf
+++ b/src/network/networkd-network-gperf.gperf
@@ -73,6 +73,9 @@ DHCP.RequestBroadcast,         config_parse_bool,                              0
 DHCP.CriticalConnection,       config_parse_bool,                              0,                             offsetof(Network, dhcp_critical)
 DHCP.VendorClassIdentifier,    config_parse_string,                            0,                             offsetof(Network, dhcp_vendor_class_identifier)
 DHCP.RouteMetric,              config_parse_unsigned,                          0,                             offsetof(Network, dhcp_route_metric)
+DHCP.UseTimezone,              config_parse_bool,                              0,                             offsetof(Network, dhcp_timezone)
+DHCPServer.EmitTimezone,       config_parse_bool,                              0,                             offsetof(Network, dhcp_server_emit_timezone)
+DHCPServer.Timezone,           config_parse_timezone,                          0,                             offsetof(Network, dhcp_server_timezone)
 Bridge.Cost,                   config_parse_unsigned,                          0,                             offsetof(Network, cost)
 Bridge.UseBPDU,                config_parse_bool,                              0,                             offsetof(Network, use_bpdu)
 Bridge.HairPin,                config_parse_bool,                              0,                             offsetof(Network, hairpin)
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index 8f773e738d..3619e3160c 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -124,7 +124,8 @@ static int network_load_one(Manager *manager, const char *filename) {
                          "Address\0"
                          "Route\0"
                          "DHCP\0"
-                         "DHCPv4\0"
+                         "DHCPv4\0" /* compat */
+                         "DHCPServer\0"
                          "Bridge\0"
                          "BridgeFDB\0",
                          config_item_perf_lookup, network_network_gperf_lookup,
@@ -258,6 +259,8 @@ void network_free(Network *network) {
         condition_free_list(network->match_kernel);
         condition_free_list(network->match_arch);
 
+        free(network->dhcp_server_timezone);
+
         free(network);
 }
 
@@ -849,3 +852,38 @@ int config_parse_hostname(
         *hostname = hostname_cleanup(hn);
         return 0;
 }
+
+int config_parse_timezone(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        char **timezone = data, *tz = NULL;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+
+        r = config_parse_string(unit, filename, line, section, section_line, lvalue, ltype, rvalue, &tz, userdata);
+        if (r < 0)
+                return r;
+
+        if (!timezone_is_valid(tz)) {
+                log_syntax(unit, LOG_ERR, filename, line, EINVAL, "Timezone is not valid, ignoring assignment: %s", rvalue);
+                free(tz);
+                return 0;
+        }
+
+        free(*timezone);
+        *timezone = tz;
+
+        return 0;
+}
diff --git a/src/network/networkd.h b/src/network/networkd.h
index 5340922bf1..a337ea7bf0 100644
--- a/src/network/networkd.h
+++ b/src/network/networkd.h
@@ -143,12 +143,15 @@ struct Network {
         bool dhcp_broadcast;
         bool dhcp_critical;
         bool dhcp_routes;
+        bool dhcp_timezone;
         unsigned dhcp_route_metric;
         AddressFamilyBoolean link_local;
         bool ipv4ll_route;
         union in_addr_union ipv6_token;
 
         bool dhcp_server;
+        char *dhcp_server_timezone;
+        bool dhcp_server_emit_timezone;
 
         bool use_bpdu;
         bool hairpin;
@@ -461,3 +464,5 @@ int config_parse_ipv6_privacy_extensions(const char *unit, const char *filename,
 
 /* Hostname */
 int config_parse_hostname(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
+
+int config_parse_timezone(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);